(1) Field of the Invention
The present invention relates generally to transducer arrays, and more particularly to a composite transducer array that provides a broadband frequency response over a wide field of view.
(2) Description of the Prior Art
A variety of sonar applications such as vehicle homing require the steering of acoustic beams over a wide field-of-view. Existing homing array technology uses numerous narrowband and high-power longitudinal tonpilz resonators to form the aperture of an active transducer. Each tonpilz resonator consists of several active and inactive mechanical components that work together as a spring-mass, single degree-of-freedom system. Unfortunately, tonpilz resonators are expensive to fabricate and offer only a limited operational bandwidth above their first length mode resonance.
To address operational bandwidth limitations of tonpilz resonators, recent work has focused on constructing multi-resonance tonpilz elements that have significantly greater bandwidth than that of the original single-mode tonpilz resonators. However, the fixed-size radiation head inherent to tonpilz resonators prevent their use in a “frequency agile” design in which array apertures can be varied in size.